FAIRFIELD COUNTY, Conn. -- Nearly 80 percent of the overhead power lines on Metro-North's New Haven Line between Southport and Bridgeport have been replaced, opening up four train tracks through that area for the first time in four years, Gov. Dannel Malloy announced Tuesday, May 6.

With the replacement of “catenary” wires in that area, Metro-North will be able to route peak-period trains on all four tracks in this 7-mile area for the first time since 2010. The project is funded and managed by the Connecticut Department of Transportation.

“The New Haven Line is the single busiest commuter rail in the country, yet much of the power source and equipment that is critical to providing residents with the safe and reliable service we expect is deteriorating and needs to be replaced,” said Malloy. “We are making excellent progress to update and upgrade all aspects of our commuter rail infrastructure and, in particular, replacing the aging catenary wires will give us greater operating flexibility and the ability to get around potential service disruptions during emergencies.

"Now that all tracks between Southport and Bridgeport are available for service for the first time in years, we will see more reliable service and scheduling for trains during peak periods, the elimination of temporary speed restrictions and little to no impact on trains when there are operational problems in this section of the railroad.”

The work on the overhead power lines, which began in 2007, had required two of the four tracks to be out of service, resulting in slower trains through the work zone and when changing tracks at either end of the construction area.

One of the two tracks was returned to service on April 26 in time for the May 11 schedule change, and the other is expected to return later this month.

The next phase of the project will take place in two areas — from East Norwalk to Green’s Farms and from Bridgeport to Devon — involving the replacement of about 10.5 miles of catenary along the tracks and in the Bridgeport rail maintenance yard. That work will begin at the end of August.

Once completed, the $386.5 million project will have replaced all the original catenary first erected in 1907. The old “fixed termination” catenary system — which can sag or contract due to changes in temperature, resulting in wire damage — is being replaced with a state-of-the-art constant tension system.

Four open-deck railroad bridges were also replaced in Bridgeport and Fairfield at North Benson Road, Fairfield Avenue, South Avenue and Westway Road. The new closed-deck ballast-style bridges provide a smoother ride. Another bridge at Main Street in Bridgeport was removed and filled in with backfill material flanked by retaining walls.